Braking device for use in winding multiple strips upon a common mandrel

ABSTRACT

In winding multiple strips of magnetic material, the strips, in passing on their way to a common winding mandrel, are applied to engage an arc-shaped area of the cylindrical surface formed by the outer edge surfaces of a plurality of juxtaposed braking rings rotatively mounted upon a stationary drum. The rings are spaced by intervening spacing rings being of lesser diameter and mounted upon the drum to move freely axially but locked against relative rotation therewith. The stack of alternate braking and spacing rings is held under axial pressure to create a predetermined resilient pressure between the adjoining rings, and the strips to be wound are held in contact with the braking rings by permanent magnets embedded in or a ribbon of magnetic material affixed to the outer surfaces of the rings.

United States Patent Gaudin *May 30, 1972 [54] BRAKING DEVICE FOR USE IN WINDING MULTIPLE STRIPS UPON A COMMON MANDREL [72] inventor: Jean Gaudln, Montigny les Cormeilles,

France [73] Assignee: Societe De Constructions Mecaniques De Creii l Notice: The portion of the term of this patent subsequent to Sept. 23, 1986, has been disclaimed [22) Filed: Sept. 9, i969 [21] Appl. No.: 856,928

[30] Foreign Application Priority Data Jan. 23, 1969 France ..690l164 [52] U.S. Cl ..242/75.2, 226/93, 226/l90 [51] Int. Cl. t ..B65h 23/10, B65h 77/00 [58] Field ofSearch ..242/56.2, 56.9, 75.2; 226/195 56] References Cited UNITED STATES PATENTS 3,380,686 4/1968 Gaudin ..242/75.2

Primary Examiner-Stanley N. Gilreath Asristan! Examiner-Gregory A. Walters Attorney-Greene & Durr ABSTRACT In winding multiple strips of magnetic material, the strips, in passing on their way to a common winding mandrel, are applied to engage an arc-shaped area of the cylindrical surface formed by the outer edge surfaces of a plurality of juxtaposed braking rings rotatively mounted upon a stationary drum. The rings are spaced by intervening spacing rings being of lesser diameter and mounted upon the drum to move freely axially but locked against relative rotation therewith. The stack of alternate braking and spacing rings is held under axial pressure to create a predetermined resilient pressure between the adjoining rings, and the strips to be wound are held in contact with the braking rings by permanent magnets embedded in or a ribbon of magnetic material affixed to the outer surfaces of the rings.

3 Claims, 4 Drawing figures PATENTEnmao I972 A R 1 9 4:124. m W3 W 20 51-a INVE TOR L/Z /IN AUDI/V mam. 2am

ATTO R N EY BRAKING DEVICE FOR USE IN WINDING MULTIPLE STRIPS UPON A COMMON MANDREL The present invention relates to tensioning devices for use in conjunction with the winding of multiple strips upon a common mandrel, to ensure a unifonn tightness of the coils wound upon said mandrel.

A main object of the invention is the provision of means to control the individual winding tensions of the strips, in such a manner as to keep the same at a substantially constant value throughout the winding operations and to result in coils of substantially uniform tightness or closeness of the winding turns.

ln metallurgical and other operations, it is customary to slit webs of great length and width by unwinding the same from a supply roll, the strips or webs being cut in the longitudinal direction by means of shearing mechanism, such as circular blades or cutters, and the partial strips being thereafter wound upon a common mandrel.

It is furthennore customary in practice, in carrying out winding operations of this type and for equalizing purposes, to provide a catenary sag between the shearing and winding mechanisms and to maintain this sag, such as by operating the shearing devices in synchronism with the winding mandrel.

In the employment of a combined slitting and winding operation of this type, it is observed, for reasons well known, that the height of the sag is not constant for each of the partial strips cut from an original wider strip, whereby to result in differences in the linear velocities of the strips being wound and, in turn, in nonuniform winding tensions or irregularly wound coils upon the common mandrel.

As a consequence, when several strips, produced for example from a single strip by slitting, or originating from any other source involving variations of the strip velocities, have to be wound upon a common mandrel in such a way that the wind ing tensions of all the strips are uniformly close, each of the strips must of necessity be subjected to some braking action prior to winding.

There are described in the copending U.S. Pat. applications Ser. Nos. 668,422 filed Sept. I8, 1967, now U.S. Pat. No. 3,468,494 and 793,793 filed Jan. 24, 1969, now U.S. Pat. No. 3,547,332, filed by the same applicant, tensioning devices for use in conjunction with the winding of multiple strips of any width or combination of widths upon a common mandrel, said devices affording an individual control of the strip tensioning force, to result in substantially uniformly wound coils upon said mandrel.

The tensioning devices described by the aforementioned application comprise essentially a multiplicity of aligned and superposed braking rings rotatively mounted upon a drum forming a support therefore. The rings, the peripheral surfaces of which constitute a cylindrical surface for the application thereto and in frictional contact with a predeten-nined fractional arc-shaped bearing surface of the strips, are maintained under axial pressure by suitable resilient pressure-applying means, such as an inflatable toroidal chamber or a multiplicity of such chambers. The braking rings alternate with spacing rings of lesser diameter mounted upon the drum or support for free axial movement but locked against relative rotation therewith. The multiple strips applied to said bearing surface are maintained in frictional pressure engagement therewith, in such a manner as to enable rotation of the braking rings relative to the spacing rings, to individually control or readjust the winding tensions of the strips. Variations of the strip velocities are thus readily equalized by relative rotation or slippage of the respective braking rings being engaged by the strips. As will be understood, in order to effect an automatic tensionequalizing operation of this type, or to result in coils of equal winding tension or tightness of the winding turns, the constant pressure between the strips and braking rings must be in excess of the stack pressure between the adjoining braking and spacing rings.

In the known tensioning devices, the strips are maintained in proper pressure engagement with the braking rings by means of pneumatic pressure by enclosing the upper part of the device adjacent to the strip bearing surface by a casing fitted with suitable inlet means for the admission of compressed air under s itable pressure. Such an arrangement, besides increasing manufacturing costs by the requirement of auxiliary devices, such as a source of compressed air, conduit and pressure control means, etc., requires constant supervision, to ensure proper strip pressure in relation to stack pressure, in the manner explained and pointed out.

Accordingly, an object of the present invention is the provision of a multiple strip tensioning device of the referred to type, wherein a substantially constant pressure upon the strips is applied by relatively simple means and practically no supervision or readjustment is required throughout substantially the entire life of the device.

A more specific object of the invention is the provision of strip pressure-applying means in a tensioning device of the referred to type requiring no auxiliary devices exterior of the tensioning device proper.

The invention, both as to the foregoing objects as well as to novel objects thereof, will be better understood from the following detailed description, taken in conjunction with the accompanying drawing forming part of this disclosure and in which;

FIG. I is a side view, shown partly in section, of a multiple strip tensioning device of the type according to the abovementioned copending applications;

FIG. 2 is a fragmentary view, to an enlarged scale, showing the upper left hand portion of FIG. I modified in accordance with the improvement of the present invention;

FIG. 3 is a section taken on line 3-3 ofFlG. 2; and

FIG. 4, being similar to FIG. 3, shows a modification of the invention.

Like reference numerals denote like parts in the different views of the drawing.

With the foregoing objects in view, the present invention, being especially applicable to the winding of strips consisting at least in part of magnetic material, involves generally the use of magnetic attraction between the strips and the bearing surface provided by the braking rings in a tensioning or braking device of the general type described herein. For this purpose the outer peripheral surfaces of the braking rings are suitably magnetized or fitted with permanent magnet means, such as in the form of a multiplicity of permanent magnet elements embedded in the rings, preferably during the casting thereof where the rings consist of a moldable material such as aluminum. Alternatively, the rings may have affixed thereto sheets or ribbons of permanent magnetic material being suitably magnetized to attract the strips to be wound with sufficient pressure, or to prevent relative slippage between the rings and strips during the winding operations. Where the rings themselves are of magnetic material, they are advantageously covered with a layer of nonmagnetic materialv Other suitable means may be utilized to ensure adequate adherence by magnetic attraction between the strips and braking rings during the operation of the tensioning device, including the use of electromagnets, although a special winding or windings will be required in the latter case in conjunction with a slip-ring and brush contacting device for supplying operating current to the magnet winding or windings. An advantage of this embodiment is the possibility of a close control of the magnetic attraction or pressure between the strips and braking rings, to ensure optimum operation conditions and to suit existing requirements, in a manner as will become further apparent by the description in reference to the drawing as follows.

Freely rotatively mounted on a cylindrical drum 1, FIG. 1, connected at its end faces 2 to an arbor 3, are a plurality of aligned and superposed braking rings 4 separated from each other by relatively thin spacing rings 5 of lesser outer diameter than the rings 4. The spacing rings 5 have projections 6 at their inner periphery, in the form of castellations or the like, which engage in corresponding longitudinal grooves 7 in the drum 1, whereby the rings 5 are rigid in rotation with the drum, in contrast to the freely rotating rings 4, the latter and the rings 5 being, however, axially slidable, for the purpose as will become apparant as the description proceeds.

The drum 1 forms or carries a fixed abutment 8 at one end and a head 9 at its other end, forming at its side facing the rings 4 an annular housing 10, FIG. 2, adapted to receive an inflatable toroidal chamber 11 supported by its outer periphery engaging the annular wall of the head 9 which bounds the housing 10 towards the outside and against the drum 1 by its internal periphery. The interior face of the inflatable chamber 11 is applied against an annular spacing ring 13 disposed between said chamber and the first ring of the stack of rings 4. Any suitable means may be provided to supply compressed air or a like pressurized fluid t0 the chamber ll.

Furthermore, any other means may be provided to produce a suitable stack pressure on the alternate braking rings 4 and spacing rings 5, such as a plurality of inflatable chambers, one for each adjacent pair of braking and spacing rings, as shown in the copending US. Pat. application Ser. No. 793,793, or any equivalent pressure-applying means.

The device is completed by an open-ended casing 17 enclosing the upper portion of the drum 1 and fitted with suitable inlets for the admission of compressed air into the chamber enclosed by said casing and drum. The casing substantially engages the strips 15, 16, etc. being wound which pass on to the rings 4, in such a manner as to provide a fluid escape gap, the supply of compressed air being sufi'icient to compensate for the air escaping between the edge of the casing and the drum or strips applied thereto.

In operation, the introduction of compressed air into the chamber 11 causes the latter to resiliently apply the rings 4 against the rings 5 via the spacing member 13, at the same time as the compressed air contained in the casing 17 brings about the application of the strips 15, 16, against the arcshaped peripheral bearing surface of the rings 4 within said casing.

Evidently, the pressure of inflation of the expanding chamber It may be adjustable, in an effort to vary the degree of closeness of the turns wound upon the common winding mandrel. In any case, the strips must be applied against the periphery of the rings 4 by the effect of the compressed air in the casing 15 with a force exceeding the friction exerted between the braking rings 4 and spacing rings 5.

The drum 1 may be stationary or rotatively supported against a constant braking force, as more clearly described in the copending US. Pat. application Ser. No. 668,422.

The function of the braking device will be further understood from the following. Assuming, for arguments sake, the rings 4 to be connected at their peripheries, to form an integral cylindrical bearing surface for the strips 15, 16 friction braking is effected between the rings 4 and the rings 5 by the former being driven by the strips, provided a proper pressure to be applied to the outside of the strips by the compressed air in the casing 17. Assuming further all the strips to be fed to the device at the same initial velocity, the strips will then be braked or decelerated equally, determined by the braking force applied by the toroidal chamber 11, whereby to result in a predetermined uniform winding tension or tightness of the coils wound upon the common mandrel.

0n the other hand, if the initial velocities of the strips differ from each other, as in the majority of practical cases, it will no longer be possible to ensure a uniform winding tension, in that some of the strips will be decelerated to a more or lesser degree than the remainder of the strips by the common braking force applied by the inflated chamber 1 1. This difficulty is overcome by the subdivision of the braking surface into a multiplicity of discrete and narrow areas, provided by the edge surfaces of the rings 4, in such a manner as to allow relative rotation or individual slippage of the rings engaged by the different strips, to in turn enable a ready equalization of the varying strip winding tensions and to result in substantially unifomilywound coils. I

According to the improvements of the present invention, as

shown by FIG. 24, adequate friction between the strips l5, l6 and the bearing surface provided by the rings 4 is produced by the direct embedment in the rings 4 of slightly curved and suitably spaced permanent magnet elements 20, FIGS. 2 and 3, being flush with the outer peripheral surfaces of the rings. Alternatively, a ribbon of magnetic material 21 may be affixed to the peripheral cylindrical surface of each of the rings 4. In either case of separate magnet elements 20 or a continuous magnetized ribbon 21, magnetization should be in the radial direction, to provide optimum attraction between the strips and the braking rings 4 in excess of the stack pressure between the latter and the spacing rings 5. Where the rings themselves are of magnetic material, a spacing strip or layer of nonmagnetic material should be interposed between the strips and rings, to prevent sticking and other defects.

In the foregoing the invention has been described in reference to an illustrative or exemplary device. It will be evident, however, that variations and modifications as well as the substitution of equivalent parts for those shown for illustration, arny be made without departing from the broader scope and spirit of the invention.

I claim:

1. A tensioning device for use in the winding of a plurality of strips of magnetic material upon a common mandrel comprising in combination:

1. a drum,

2. a multiplicity of braking rings freely rotatively mounted upon said drum for frictionally supporting a plurality of juxtaposed strips on their way to said mandrel engaging an arc-shaped area of the cylindrical surface formed by the outer peripheral edge surfaces of said rings,

3. spacing rings of lesser outer diameter intervening between said braking rings and locked against rotation but being freely axially movable relative to said drum,

4. resilient means to exert axial pressure upon the stack of alternate braking and spacing rings, and

5. permanent magnet means distributed circumferentially on said breaking rings, to maintain a frictional pressure between said strips and said rings in excess of the stack pressure between the adjacent braking and spacing rings.

2. A tensioning device as claimed in claim 1, wherein said magnet means is comprised of a plurality of spaced permanent magnet elements in the form of curved plates embedded in and flush with the peripheral surfaces of said rings.

3. A tensioning device as claimed in claim 1, wherein said magnet means is comprised of a permanent magnet ribbon affixed to each of the peripheral surfaces of said braking rings. 

1. A tensioning device for use in the winding of a plurality of strips of magnetic material upon a common mandrel comprising in combination:
 1. a drum,
 2. a multiplicity of braking rings freely rotatively mounted upon said drum for frictionally supporting a plurality of juxtaposed strips on their way to said mandrel engaging an arcshaped area of the cylindrical surface formed by the outer peripheral edge surfaces of said rings,
 3. spacing rings of lesser outer diameter intervening between said braking rings and locked against rotation but being freely axially movable relative to said drum,
 4. resilient means to exert axiAl pressure upon the stack of alternate braking and spacing rings, and
 5. permanent magnet means distributed circumferentially on said breaking rings, to maintain a frictional pressure between said strips and said rings in excess of the stack pressure between the adjacent braking and spacing rings.
 2. a multiplicity of braking rings freely rotatively mounted upon said drum for frictionally supporting a plurality of juxtaposed strips on their way to said mandrel engaging an arc-shaped area of the cylindrical surface formed by the outer peripheral edge surfaces of said rings,
 2. A tensioning device as claimed in claim 1, wherein said magnet means is comprised of a plurality of spaced permanent magnet elements in the form of curved plates embedded in and flush with the peripheral surfaces of said rings.
 3. A tensioning device as claimed in claim 1, wherein said magnet means is comprised of a permanent magnet ribbon affixed to each of the peripheral surfaces of said braking rings.
 3. spacing rings of lesser outer diameter intervening between said braking rings and locked against rotation but being freely axially movable relative to said drum,
 4. resilient means to exert axiAl pressure upon the stack of alternate braking and spacing rings, and
 5. permanent magnet means distributed circumferentially on said breaking rings, to maintain a frictional pressure between said strips and said rings in excess of the stack pressure between the adjacent braking and spacing rings. 